A technique in the field of radiation detectors is disclosed in Patent document 1 listed below. Patent document 1 discloses a radiation detecting device including an amorphous semiconductor thick film, a voltage applying electrode, and a high-resistance film with solvent resistance and carrier selectivity disposed between the amorphous semiconductor thick film and the voltage applying electrode so as to cover the entire surface of the amorphous semiconductor thick film. Thus, the radiation detecting device of Patent document 1 includes a high-resistance film to reduce an increase in dark current even when a high bias is applied.